Early on when I started working on airport problems at Lyft, airport regulators started requiring that Lyft build a system that would allow airport staff to have real time data about rideshare just like they already had for other commercial vehicles.
Legacy ground transportation providers use permanently affixed transponders that tag sensors in the roadway to provide this data. But the big challenge for Lyft is that drivers use their personal vehicles.
The solution was to build a geofence based tracking system that would log driver entries, exits, pickups, and dropoffs on airport property. These events would have vehicle specific information to help airport regulators better manage and audit the commercial activity on their premises.
Over the years, I PM'ed many iterations of this system. Some of the changes we made were at the request of regulators, like adding sub-geofences and new events, and some changes were made for Lyft's own efficiency and operations.